2023 Vol. 47, No. 11

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2023-11 Contents
2023, 47(11): 1-2.
Abstract:
PARTICLES AND FIELDS
Prospects of CP violation in Λ decay with a polarized electron beam at the STCF
Sheng Zeng, Yue Xu, Xiao-Rong Zhou, Jia-Jia Qin, Bo Zheng
2023, 47(11): 113001. doi: 10.1088/1674-1137/ace9c5
Abstract:
Based on \begin{document}$ 1.89 \times 10^8 J/\psi \rightarrow \Lambda \bar{\Lambda} $\end{document} Monte Carlo (MC) events produced from a longitudinally-polarized electron beam, the sensitivity of the \begin{document}$ CP $\end{document} violation of Λ decay is studied using fast simulation software. In addition, the \begin{document}$ J/\psi \rightarrow \Lambda \bar{\Lambda} $\end{document} decay can be used to optimize the detector response using the interface provided by the fast simulation software. In the future, the STCF is expected to obtain 3.4 trillion \begin{document}$ J/\psi $\end{document} events, and the statistical sensitivity of the \begin{document}$ CP $\end{document} violation of Λ decay via the \begin{document}$ J/\psi \rightarrow \Lambda \bar{\Lambda} $\end{document} process is expected to reach \begin{document}$ \mathcal O (10^{-5}) $\end{document} when the electron beam polarization is 80%.
JUNO sensitivity on proton decay pνK+ searches
Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli, Thilo Birkenfeld, Sylvie Blin, David Blum, Simon Blyth, Anastasia Bolshakova, Mathieu Bongrand, Clément Bordereau, Dominique Breton, Augusto Brigatti, Riccardo Brugnera, Riccardo Bruno, Antonio Budano, Mario Buscemi, Jose Busto, Ilya Butorov, Anatael Cabrera, Barbara Caccianiga, Hao Cai, Xiao Cai, Yanke Cai, Zhiyan Cai, Riccardo Callegari, Antonio Cammi, Agustin Campeny, Chuanya Cao, Guofu Cao, Jun Cao, Rossella Caruso, Cédric Cerna, Jinfan Chang, Yun Chang, Pingping Chen, Po-An Chen, Shaomin Chen, Xurong Chen, Yi-Wen Chen, Yixue Chen, Yu Chen, Zhang Chen, Jie Cheng, Yaping Cheng, Alexey Chetverikov, Davide Chiesa, Pietro Chimenti, Artem C
2023, 47(11): 113002. doi: 10.1088/1674-1137/ace9c6
Abstract:
The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the \begin{document}$ p\to \bar{\nu} K^+ $\end{document} mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via \begin{document}$ p\to \bar{\nu} K^+ $\end{document} is 36.9% ± 4.9% with a background level of \begin{document}$0.2\pm 0.05({\rm syst})\pm $\end{document}\begin{document}$ 0.2({\rm stat})$\end{document} events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is \begin{document}$ 9.6 \times 10^{33} $\end{document} years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies.
Determination of the resonant parameters of excited vector strangenia with ${\boldsymbol e^+ \boldsymbol e^-\to\boldsymbol\eta\boldsymbol\phi }$ data
Wenjing Zhu, Xiaolong Wang
2023, 47(11): 113003. doi: 10.1088/1674-1137/acf034
Abstract:
We determine the resonant parameters of the vector states \begin{document}$ \phi(1680) $\end{document} and \begin{document}$ \phi(2170) $\end{document} by performing a combined fit to the \begin{document}$ e^+e^-\to \eta\phi $\end{document} cross sections from the threshold to \begin{document}$ 2.85\; {\rm{GeV}} $\end{document} measured by the BaBar, Belle, BESIII, and CMD-3 experiments. The mass \begin{document}$ (1678 ^{+5}_{-3} \pm 7)\; {{\rm{MeV}}}/c^2 $\end{document} and width \begin{document}$ (156 \pm 5 \pm 9)\; {\rm{MeV}} $\end{document} are obtained for \begin{document}$ \phi(1680) $\end{document}, and the mass \begin{document}$ (2169 \pm 5 \pm 6)\; {{\rm{MeV}}}/c^2 $\end{document} and width \begin{document}$ (96^{+17}_{-14} \pm 9)\; {\rm{MeV}} $\end{document} are obtained for \begin{document}$ \phi(2170) $\end{document}. The statistical significance of \begin{document}$ \phi(2170) $\end{document} is \begin{document}$ 7.2\sigma $\end{document}. Depending on the interference between \begin{document}$ \phi(1680) $\end{document}, \begin{document}$ \phi(2170) $\end{document}, and a non-resonant \begin{document}$ \eta\phi $\end{document} amplitude in the nominal fit, we obtain four solutions and \begin{document}$ \Gamma^{ e^+e^-}_{ \phi(1680)}\cdot {\cal B}[\phi(1680)\to\eta\phi] = (79 \pm 4 \pm 16) $\end{document}, \begin{document}$ (127\pm 5 \pm 12) $\end{document}, \begin{document}$ (65^{+5}_{-4} \pm 13) $\end{document} or \begin{document}$ (215^{+8}_{-5} \pm 11)\; {\rm{eV}} $\end{document}, and \begin{document}$ \Gamma^{ e^+e^-}_{ \phi(2170)}\cdot {\cal B}[\phi(2170)\to\eta\phi] = (0.56^{+0.03}_{-0.02}\pm 0.07) $\end{document}, \begin{document}$ (0.36^{+0.05}_{-0.03}\pm 0.07) $\end{document}, \begin{document}$ (38 \pm 1 \pm 5) $\end{document} or \begin{document}$ (41 \pm 2 \pm $\end{document}\begin{document}$ 6)\; {\rm{eV}} $\end{document}. We also search for the production of \begin{document}$ X(1750)\to\eta\phi $\end{document}, and the significance is only \begin{document}$ 2.0\sigma $\end{document}. We then determine the upper limit of \begin{document}$ \Gamma^{ e^+e^-}_{X(1750)}\cdot {\cal B}[X(1750) \to \eta\phi] $\end{document} at the 90% confidence level.
CP asymmetry from the resonance effect of the B meson decay process with π and K final states
Xi-Liang Yuan, Gang Lü, Na Wang, Li-Ying Zhang, Xin-Heng Guo
2023, 47(11): 113101. doi: 10.1088/1674-1137/acf037
Abstract:
We present the novel \begin{document}$ V\rightarrow K^{+}K^{-} (V=\phi, \rho, \omega) $\end{document} resonance, which generates a strong phase associated with vector meson resonances, leading to significant CP asymmetry in the interference region. The \begin{document}$ \phi \rightarrow K^{+}K^{-} $\end{document}, \begin{document}$ \rho \rightarrow K^{+}K^{-} $\end{document}, and \begin{document}$ \omega \rightarrow K^{+}K^{-} $\end{document} resonances arise from the mixing of the vector mesons ϕ, ρ, and ω. We calculate the CP asymmetry from the decay mode of \begin{document}$ B \rightarrow KK\pi(K) $\end{document}. Meanwhile, the localized CP asymmetries are presented and a detailed analysis is performed. The CP asymmetry from the decay mode of \begin{document}$ {B}^{-}\rightarrow \phi\pi^{-}\rightarrow K^{+}K^{-}\pi^{-} $\end{document} is also presented in our framework, which is highly consisted with that of the LHC experiment. The introduced CP asymmetry can provide a favorable theoretical support for experimental exploration in the future.
Possible molecular states from interactions of charmed strange baryons
Dan Song, Shu Chen, Shu-Yi Kong, Jun He
2023, 47(11): 113102. doi: 10.1088/1674-1137/acf48c
Abstract:
In this study, we investigate possible molecular states composed of two charmed strange baryons from the\begin{document}$ \Xi_c^{(',*)}{\Xi}_c^{(',*)} $\end{document} interaction and their hidden-charm hidden-strange partners from the \begin{document}$ \Xi_c^{(',*)}\bar{\Xi}_c^{(',*)} $\end{document} interaction. With the aid of heavy quark chiral effective Lagrangians, the interactions of charmed strange baryons are described with light meson exchanges. The potential kernels are constructed and inserted into the quasipotential Bethe–Salpeter equation. The bound states are produced from most interactions considered, which suggests that strong attractions exist widely between the charmed strange baryons. Experimental search for these types of molecular states is suggested in future high-precision measurements.
NUCLEAR PHYSICS
New measurement of 4He and proton decays from resonant states in 19Ne
Kai Ma, Yan-Lin Ye, Cheng-Jian Lin, Jia-Hao Chen, Dong-Xi Wang, Jia-Xing Han, Hui-Ming Jia, Lei Yang, Li-Sheng Yang, Zi-Yao Hu, Ying Chen, Wei-Liang Pu, Gen Li, Zhi-Wei Tan, Da-Hu Huang, Tian-Peng Luo, Shan-Hao Zhong, Jian-Ling Lou, Xiao-Fei Yang, Zhi-Huan Li, Qi-Te Li, Jin-Yan Xu, Zai-Hong Yang, Kang Wei
2023, 47(11): 114001. doi: 10.1088/1674-1137/acc16f
Abstract:
A \begin{document}$ ^6 $\end{document}Li(\begin{document}$ ^{16} $\end{document}O,\begin{document}$ ^{19} $\end{document}Ne\begin{document}$ ^* $\end{document})\begin{document}$ ^3 $\end{document}H multi-nucleon transfer-reaction experiment was performed to populate the highly excited states in \begin{document}$ ^{19} $\end{document}Ne. The subsequent decay particles, \begin{document}$ ^4 $\end{document}He or protons from the \begin{document}$ ^{19} $\end{document}Ne resonant states, were detected in coincidence with the recoil \begin{document}$ ^3 $\end{document}H. The excitation-energy spectra of \begin{document}$ ^{19} $\end{document}Ne were reconstructed using the detected proton or \begin{document}$ ^4 $\end{document}He and the deduced \begin{document}$ ^{18} $\end{document}F or \begin{document}$ ^{15} $\end{document}O data, respectively. A broad resonance at about 7.85 MeV (1/2\begin{document}$ ^+ $\end{document}) was observed, with partial decay widths different from the previously reported values, which may have a significant impact on the destruction of \begin{document}$ ^{18} $\end{document}F in astrophysical processes. Several resonances up to very high excitation energies have been identified with a large α-clustering strength, which confirm the formation of the cluster structure with a one-hole configuration in light nuclei and encourage further systematic studies of the cluster structure in \begin{document}$ ^{19} $\end{document}Ne.
Measurement of 169Tm(n, 2n)168Tm reaction cross sections from 12 to 19.8 MeV
Chuanxin Zhu, Hairui Guo, Jia Wang, Pu Zheng, Xinxin Lu, Tonghua Zhu
2023, 47(11): 114101. doi: 10.1088/1674-1137/acf287
Abstract:
The cross sections of the 169Tm(n, 2n)168Tm reaction have been measured at incident energies of 12 to 19.8 MeV using the activation technique, relative to the 93Nb(n, 2n)92mNb reaction. Thulium (Tm) samples were irradiated on the surface of a two-ring orientation assembly with neutrons produced from the 3H(d, n)4He reaction at the 5SDH-2 1.7-MV Tandem accelerator in China. Theoretical model calculations were performed. The present data were then compared with previous experimental data and available evaluated data. This study provides more precise nuclear data for improvement of future evaluations.
Study of neutron density fluctuation and neutron-proton correlation in Au+Au collisions using PYTHIA8/Angantyr
Zuman Zhang, Sha Li, Ning Yu, Jianping Lin, Shuang Li, Siyu Tang, Daicui Zhou
2023, 47(11): 114102. doi: 10.1088/1674-1137/acf65c
Abstract:
Utilizing the PYTHIA8 Angantyr model, which incorporates the multiple-parton interaction (MPI) based color reconnection (CR) mechanism, we study the relative neutron density fluctuation and neutron-proton correlation in Au+Au collisions at \begin{document}$\sqrt{s_{_{NN}}}$\end{document} = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV. In this study, we not only delve into the dependence of these two remarkable observations on rapidity, centrality, and energy, but also analyze their interplay with the MPI and CR. Our results show that the light nuclei yield ratio of protons, deuterons, and tritons, expressed by the elegant expression \begin{document}$N_tN_p/N_d^2$\end{document}, remains unchanged even as the rapidity coverage and collision centrality increase. Interestingly, we also reveal that the effect of CR is entirely dependent on the presence of the MPI; CR has no impact on the yield ratio if the MPI is off. Our findings further demonstrate that the light nuclei yield ratio experiences a slight increase with increasing collision energy, as predicted by the PYTHIA8 Angantyr model; however, it cannot describe the non-monotonic trend observed by the STAR experiment. Based on the Angantyr model simulation results, it is essential not to overlook the correlation between neutron and proton fluctuations. The Angantyr model is a good baseline for studying collisions in the absence of a quark-gluon plasma system, given its lack of flow and jet quenching.
Simple model for cluster radioactivity half-lives in trans-lead nuclei
Xiao-Yan Zhu, Song Luo, Lin-Jing Qi, Dong-Meng Zhang, Xiao-Hua Li, Wen-Bin Lin
2023, 47(11): 114103. doi: 10.1088/1674-1137/acf48a
Abstract:
In this study, considering the modified preformation probability \begin{document}$ P_c $\end{document} to be \begin{document}$\log_{10}P_c= $\end{document}\begin{document}$ ({A_c-1})/{3}\log_{10}P_\alpha + \,c'$\end{document}, where \begin{document}$ P_\alpha $\end{document} and \begin{document}$ c' $\end{document} are the α-particle preformation probability and an adjustable parameter proposed by Wang et al. [Chin. Phys. C 45, 044111 (2021)], respectively, we extend a new simple model put forward by Bayrak [J. Phys. G 47, 025102 (2020)] to systematically study the cluster radioactivity half-lives of 28 trans-lead nuclei ranging from \begin{document}$\rm{^{222}Fr}$\end{document} to \begin{document}$ \rm{^{242}Cm} $\end{document}, which is based on the Wentzel-Kramers-Brillouin approximation and Bohr–Sommerfeld quantization condition. For comparison, a universal decay law proposed by Qi et al. [Phys. Rev. C 80, 044326 (2009)], a three-parameter model-independent formula put forward by Balasubramaniam et al. [Phys. Rev. C 70, 017301 (2004)], and the semi-empirical model proposed by Tavares et al. [Eur. Phys. J. A 49, 1 (2013)] are used. Our calculated results reproduce the experimental data well, with a standard deviation of 0.818. Furthermore, we use this model to predict the cluster radioactivity half-lives of 51 possible cluster radioactive candidates whose cluster radioactivities are energetically allowed or observed but not yet quantified in NUBASE2020.
Expanding proton dripline by employing a number of muons
Lang Liu, Yongle Yu
2023, 47(11): 114104. doi: 10.1088/1674-1137/acf65d
Abstract:
Through mean-field calculations, we demonstrate that, in a large Z nucleus binding multiple muons, these heavy leptons localize within a few dozen femtometers of the nucleus. The mutual Coulomb interactions between the muons and protons can lead to a substantial decrease in proton chemical potential, surpassing 1 MeV. These findings imply that, in principle, the proton-dripline can be expanded on the nuclear chart, suggesting the possible production of nuclei with Z around 120.
Holographic Schwinger effect in an anisotropic background with Gauss-Bonnet corrections
Wen-Bin Chang, De-fu Hou
2023, 47(11): 114105. doi: 10.1088/1674-1137/acf7b6
Abstract:
Using the anti-de Sitter/conformal field theory (AdS/CFT) correspondence, we study the holographic Schwinger effect in an anisotropic background with the Gauss-Bonnet term. As the background geometry is anisotropic, we consider both cases of the test particle pair and the electric field perpendicular to and parallel to the anisotropic direction. It is shown that the Schwinger effect is enhanced in the perpendicular case when anisotropy rises. In the parallel case, this effect is reversed. Additionally, the potential barrier and the critical electric field in the parallel case are more significantly modified by anisotropy compared to the perpendicular case. We also find that the presence of the Gauss-Bonnet coupling tends to increase the Schwinger effect.
PARTICLE AND NUCLEAR ASTROPHYSICS AND COSMOLOGY
Photon motion and weak gravitational lensing in black-bounce spacetime
Furkat Sarikulov, Farruh Atamurotov, Ahmadjon Abdujabbarov, Vokhid Khamidov
2023, 47(11): 115101. doi: 10.1088/1674-1137/acedf2
Abstract:
The effect of spacetime curvature on photon motion may offer an opportunity to propose new tests on gravity theories. In this study, we investigate and focus on the massless (photon) particle motion around black-bounce gravity. We analyze the horizon structure around a gravitational compact object described by black-bounce spacetime. The photon motion and the effect of gravitational weak lensing in vacuum and plasma are discussed, and the shadow radius of the compact object is also studied in black-bounce spacetime. Additionally, the magnification of the image is studied using the deflection angle of light rays.
Continuous phase transition of the de Sitter spacetime with charged black holes and cloud of strings and quintessence
Hai-Long Zhen, Yun-Zhi Du, Huai-Fan Li, Xin-Ping Li, Li-Chun Zhang
2023, 47(11): 115102. doi: 10.1088/1674-1137/acf0b3
Abstract:
Recently, some meaningful results have been obtained by studying the phase transition, critical exponents, and other thermodynamical properties of different black holes. Especially for the Anti-de Sitter (AdS) black holes, their thermodynamical properties nearby the critical point have attracted considerable attention. However, there exists little work on the thermodynamic properties of the de Sitter (dS) spacetime with black holes. In this paper, based on the effective thermodynamical quantities and the method of the Maxwell's equal-area law, we explore the phase equilibrium for the de Sitter spacetime with the charged black holes and the cloud of string and quintessence (i.e., C-dSSQ spacetime). The boundaries of the two-phase coexistence region in both \begin{document}$P_{\rm eff}-T_{\rm eff}$\end{document} and \begin{document}$T_{\rm eff}-S$\end{document} diagrams are obtained. The coexistent curve and the latent heat of phase transition for this system are also investigated. Furthermore, we analyze the effect of parameters (the state parameter ω and the ratio of two horizon radii \begin{document}$ x=\it{r_{+}} $\end{document}/\begin{document}$ \it{r_{c}} $\end{document}) on the two-phase coexistence region boundary. The results indicate that the phase transition in C-dSSQ spacetime is analogous to that in a van der Waals fluid (vdw) system, which is determined by the electrical potential at the horizon. These results are helpful for understanding the basic properties of black holes and are also of great value for the establishment of quantum gravity.
Translation gauge field theory of gravity in Minkowski spacetime
Hang Li, Ping Wang
2023, 47(11): 115103. doi: 10.1088/1674-1137/acf0b2
Abstract:
The gravitational field \begin{document}$ h_{\mu\nu} $\end{document} with spin-2 is introduced naturally by the requirement that the Lagrangian is locally translation invariant in Minkowski spacetime. The interactions between the \begin{document}$ h_{\mu\nu} $\end{document} and spin-\begin{document}$ \dfrac 1 2 $\end{document}, 0, 1 matter fields are obtained along with the Lagrangian for the gravitational field including self-interactions. The deflection angle of light when it passes through the sun is calculated with different gauge conditions as an example. Our leading-order result is the same as that from general relativity, although the basic ideas are different. It is interesting that gravity can be described in a similar way to other fundamental interactions in Minkowski spacetime, and it may provide a new scenario for the Universe.
Phantom cosmologies from the simplest parameterization of the DE model using observational data in a BI type universe
H. Hossienkhani, F. Mahmoodi, V. Fayaz, S.A.A. Terohid, N. Azimi, Z. Zarei
2023, 47(11): 115104. doi: 10.1088/1674-1137/acf2fb
Abstract:
To scrutinize the nature of dark energy, many equations of state have been proposed. In this context, we examine the simplest parameterization of the equation of state parameter of dark energy in an anisotropic Bianchi type I universe compared with the ΛCDM model. Using different combinations of data samples, including Pantheon and Pantheon + H(z), alongside applying the minimization of the \begin{document}$ \chi^2 $\end{document} function of the distance modulus of data samples, we obtain the constrained values of cosmographic parameters in the parameterization of the dark energy scenario. One condition of the phantom barrier crossing is acquired. Several physical properties of the universe are discussed by considering the anisotropy effect and different observational data points. One should note that the deductions of the cosmological parameter verify recent observational data.
Revisiting the thermodynamics of the BTZ black hole with a variable gravitational constant
Yan-Ying Bai, Xuan-Rui Chen, Zhen-Ming Xu, Bin Wu
2023, 47(11): 115105. doi: 10.1088/1674-1137/aceee4
Abstract:
The thermodynamics of BTZ black holes are revisited with a variable gravitational constant. A new pair of conjugated thermodynamic variables are introduced, including the central charge C and chemical potential μ. The first law of thermodynamics and the Euler relationship, instead of the Smarr relationship in the extended phase space formalism, are matched perfectly in the proposed formalism. Compatible with the standard extensive thermodynamics of an ordinary system, the black hole mass is verified to be a first order homogeneous function of the related extensive variables, and restores the role of internal energy. In addition, the heat capacity has also resulted in a first order homogeneous function using this formalism, and asymptotic behavior is demonstrated at the high temperature limit. The non-negativity of the heat capacity indicates that the rotating and charged BTZ black holes are thermodynamically stable.
Thermodynamics under the impact of thermal fluctuations and quasi-normal modes of Euler-Heisenberg AdS BH in the framework of NLED
R. H. Ali, G. Abbas
2023, 47(11): 115106. doi: 10.1088/1674-1137/acf2fc
Abstract:
We study the impact of thermal fluctuations on the thermodynamics, quasi-normal modes, and phase transitions of an anti-de Sitter Euler-Heisenberg black hole (BH) with a nonlinear electrodynamic field. An anti-de Sitter Euler-Heisenberg BH with a nonlinear electrodynamic field is composed of four parameters: the mass, electric charge, cosmological constant, and Euler-Heisenberg parameter. We calculate thermodynamic variables such as Hawking temperature, entropy, volume, and specific heat, which comply with the first law of thermodynamics. First, we use this BH to determine the thermodynamics and thermal fluctuations with the Euler-Heisenberg parameter to distinguish their effect on uncorrected and corrected thermodynamical quantities. We derive the expression for corrected entropy to study the impact of thermal fluctuation with simple logarithmic corrections on unmodified thermodynamical potentials, including Helmholtz energy, pressure, Gibbs free energy, and enthalpy. The Euler-Heisenberg parameter improves BH stability at large radii. Second, we analyze the local stability of the proposed BH, and the phase shifts of the BH are also investigated using temperature and specific heat. When there is a decrease in charge and an increase in \begin{document}$ r_{+} $\end{document} and α, the temperature shifts from an unstable region to a stable one. Similarly, increases in local stability are observed with each of these parameters. Third, we use null geodesics to deal with the effects of nonlinear electrodynamics on the quasi-normal modes of the Euler-Heisenberg anti-de Sitter BH. The null geodesics provide the angular velocity and Lyapunov exponent of the photon sphere, which are the same as the real and imaginary parts of the quasi-normal modes in the eikonal limit.
Constraining the ${\boldsymbol f(\boldsymbol R,\boldsymbol T)=\boldsymbol R+\boldsymbol 2\boldsymbol\lambda \boldsymbol T} $ cosmological model using recent observational data
N. Myrzakulov, M. Koussour, Alnadhief H. A. Alfedeel, E. I. Hassan
2023, 47(11): 115107. doi: 10.1088/1674-1137/acf2fa
Abstract:
In this study, we conduct a comprehensive investigation of the cosmological model described by \begin{document}$ f(R,T) = R + 2\lambda T $\end{document} (where λ represents a free parameter) in light of the most recent observational data. By constraining the model using the \begin{document}$ Hubble $\end{document} and \begin{document}$ Pantheon $\end{document} datasets, we determine its compatibility with the observed behavior of the Universe. For this purpose, we adopt a parametric form for the effective equation of state (EoS) parameter. This parametric form allows us to describe the evolution of the EoS parameter with respect to redshift and investigate its behavior during different cosmic epochs. The analysis of the deceleration parameter reveals an accelerating Universe with a present value of \begin{document}$ q_0=-0.64^{+0.03}_{-0.03} $\end{document}, indicating the current phase of accelerated expansion. The transition redshift is found to be \begin{document}$ z_{tr}=0.53^{+0.04}_{-0.03} $\end{document}, marking the epoch of transition from deceleration to acceleration. We also analyze the evolution of important cosmological parameters, including the density parameter, pressure, effective EoS, and stability. These findings collectively demonstrate the viability of the \begin{document}$ f(R,T) $\end{document} cosmological model as a robust candidate capable of engendering the requisite negative pressure, thereby efficiently propelling cosmic expansion. Moreover, the undertaken stability analysis underscores the model's stability within the broader cosmic landscape. By providing the best-fit values for the coupling parameter λ, this approach motivates and encourages further exploration into the extensive landscape of this model and its potential applications across diverse realms of cosmology and astronomy.
Holographic entanglement entropy with Power-Maxwell electrodynamics in higher dimensional AdS black hole spacetime
Kongchen Wang, Wanhe Zhang, Weiping Yao
2023, 47(11): 115108. doi: 10.1088/1674-1137/acf48b
Abstract:
We investigate the behaviors of the scalar operator and holographic entanglement entropy in the metal/superconductor phase transition with Power-Maxwell electrodynamics in a higher dimensional background away from the probe limit. We observe that the larger parameters b and q make the condensation of the scalar operator more difficult, and the critical temperature decreases more slowly as the factors increase. In the belt geometry, the value of the entanglement entropy in the metal and superconductor phases is not only related to the the strength of the Power-Maxwell field but also to the width of the strip geometry. At the phase transition point, the discontinuous slope of entanglement entropy is universal for different model factors. It turns out that holographic entanglement entropy is a powerful tool to probe the properties of the phase transition in this holographic superconductor model.